Tulane National Primate Center (TNPRC) has one of the largest rhesus monkey breeding colonies in the US. This resource has provided animals for NIH funded research projects for several decades and is a critical component of the Center's successful research program. Because over half of all projects at TNPRC are initiated by outside investigators, this resource is also essential to the success of many NIH-funded investigators throughout the country. Several years ago TNPRC established the goal of having only specific pathogen free (SPF) monkeys at the Center. A major step toward that goal was the award of this U42 grant in 2001 to provide funds to establish an SPF Indian-origin rhesus monkey colony at TNPRC to provide monkeys for NIH-funded AIDS research. Approximately 800 animals were recruited into the U42 funded SPF colony in the first four years. The colony is expected to increase in number to 1,000 animals by the end of the last year of the current grant, meeting the goal of the original application. The objective of this application is to request funds to support an average of 900 SPF rhesus monkeys and to continue to monitor the viral status of the colony for the next 5 years. The plan is to maintain the colony at a level that will allow production of at least 300 infants each year. This will provide at least 150 animals for assignment to NIH-funded AIDS research protocols and 150 for replacement breeders. Beginning in year 2, revenue from animal sales will be returned to the grant as program income. This will begin the process of transition to a self-sustaining colony, which will be achieved by the end of the grant period.